| 摘要 |
In an earth boring device with a boring head (14) rotatable about its axis (16), which boring head for the control of its direction has a control surface (18) inclined to its axis (16) and at least one jet (20) for the discharge of a pressurized boring fluid, with the jet openings being arranged on a side of the boring head parallel to the axis of the boring head and facing away from the control surface (18), the axial spacing of the jets from the boring head tip and their stream direction are so chosen that in the use of the boring head the streams escaping from the jets reach essentially only the region of earth lying to the side of the boring head.
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